Inoculation and vaccination: smallpox, cowpox and vaccinia.
D049671:History, 18th Century; D049672:History, 19th Century; D012900:Smallpox Vaccine / Q000266:history*; D014615:Vaccinia; D014765:Viral Vaccines / Q000266:history*
D012900:Smallpox Vaccine; D014765:Viral Vaccines